<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <div @mouseleave="currentIndex = -1">
        <h2 class="all">全部商品分类</h2>
        <div class="sort">
          <div class="all-sort-list2" @click="toSearch">
            <div
              class="item"
              v-for="(c1, index) in categoryList"
              :key="c1.categoryId"
              :class="{ item_on: index === currentIndex }"
              @mouseenter="moveIn(index)"
            >
              <h3>
                <a
                  href="javascript:;"
                  :data-categoryName="c1.categoryName"
                  :data-category1Id="c1.categoryId"
                  >{{ c1.categoryName }}</a
                >
              </h3>
              <div class="item-list clearfix">
                <div class="subitem">
                  <dl
                    class="fore"
                    v-for="(c2, index) in c1.categoryChild"
                    :key="c2.categoryId"
                  >
                    <dt>
                      <a
                        href="javascript:;"
                        :data-categoryName="c2.categoryName"
                        :data-category2Id="c2.categoryId"
                        >{{ c2.categoryName }}</a
                      >
                    </dt>
                    <dd>
                      <em
                        v-for="(c3, index) in c2.categoryChild"
                        :key="c3.categoryId"
                      >
                        <a
                          href="javascript:;"
                          :data-categoryName="c3.categoryName"
                          :data-category2Id="c3.categoryId"
                          >{{ c3.categoryName }}</a
                        >
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>

      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { mapState } from "vuex";
import { debounce, throttle } from "lodash";
export default {
  name: "TypeNav",
  data() {
    return {
      currentIndex: -1, // 对比和移入的那个index是否一致
    };
  },
  methods: {
    getCategoryList() {
      this.$store.dispatch("getCategoryList");
    },
    // 不可以使用箭头函数
    moveIn: debounce(function (index) {
      this.currentIndex = index;
      // 在methods函数中不能直接使用节流函数
      // _.throttle(() => console.log(index), 1000);
    }, 300),
    toSearch(event) {
      /*
        这个函数是上面事件委派发后的回调函数
        这个函数可以被div中所有的元素点击后触发
          所以需要去判断点击的是不是我们要委派的a标签
          我们点击的a标签有三种，分别带的参数是不同的，参数我们也需要区别开来
       */
      const { categoryname, category1id, category2id, category3id } =
        event.target.dataset;
      // console.log(categoryname)
      // 如果有分类名称, 说明点击的是某个分类项
      if (categoryname) {
        // 准备query参数
        const query = { categoryName: categoryname };
        if (category1id) {
          query.category1Id = category1id;
        } else if (category2id) {
          query.category2Id = category2id;
        } else if (category3id) {
          query.category3Id = category3id;
        }

        // 准备用于跳转路由的目标location对象
        const location = {
          name: "Search",
          query,
          params: this.$route.params, // 携带上原本就有的params参数
        };

        // 跳转到搜索路由
        this.$router.push(location);
      }
    },
  },

  computed: {
    /*
      拿 state 和 getters 是在计算属性中获取
      拿 mutations 和 actions 是在methods中获取

      ...mapState(['categoryList'])
      假若名称一样，就可以使用数组映射，但这是针对直接在总的store里面的state数据

      总的state{
        categoryList:[]
      }

      模块化state，只能使用对象形式映射
      总的state{
        home:{
          categoryList:[]
        }
      }
    */
    ...mapState({
      categoryList: (state) => state.home.categoryList,
    }),
  },
  async mounted() {
    //获取数据分类
    await this.getCategoryList();
  },
};
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            _height: 200px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          &.item_on {
            background-color: gray;
            .item-list {
              display: block;
            }
          }
        }
      }
    }
  }
}
</style>
